Handhole plug



Dec. 9, 1924.

J. H. HOFFMAN .HANDHOLE PLUG Filed se t. 21. 1925 Patented l jf'ec, Q9, ld li.

i can ll n a an n .mfl .l are .t it charm a WW .t. a

HAlEEDHOLE FLU Application filed September 21, 1923.

To all whom it may concern.

Be it known that l, Jorrn lrlnnur Horrluan, a citizen of the United States, and resident ot V est Brighton, borough of Richmend, in the @tate of New York, have invented certain new and useful improvements in l landhole Plugs, of which the following is a specification.

The general object of my present invention. is to provide a simple and relatively inexpensive hand hole closure construction comprising a bushing securely mounted in the hole in the wall oi the chamber to which the closure pertains, and adapted to be expanded into snug contact with said wall by the action of the fluid pressure in said chamber against the larger inner end of a tapered plug having its smaller end inserted in said bushing from the inner side of the latter, the larger end of the plug being too large to pass through the bushing. The invention insures the smile strength and security against rupture and leakage in apparatus for high pressiu'e work, as is obtained with the use of such a tapered plug when the latter is inserted in the inner end of an opening in. the chamber wall. proper, too small to pass the base of the plug, and at the same time permits the insertion and re moval of the plug through the hole for which it forms a removable closure.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming apart of this specification; tor a better understanding oi the invention however, its advantages and specific objects at tained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated preferred embodiments of my invention.

Of the drawings:

Fig. 1 is an elevation.

Fig. 2 is a section of the line 22 of Fig. 1; and

Figs. 3 and 4; are views taken similar to Fig. 2, each illustrating a dillereut form oi construction.

In the drawings, and referring first to the construction shown in Figs. 1 and 2, A represents a metal plate forming a portion of the wall of a boiler shell, a header or other chamber for fluid under pressure. In the wall A is formed a cylindrical hand hole opening A, which is internally threaded,

Serial No. G63,94=5.

the plate 1i. forms a wall portion. -ildvantageously, as shown, the l u B is provided with l which the plate abuts again.

pass? reii in the way throi a closed by a l which small cough through the hole A, beorc the bushing B is put in place, but is too large to pass through the hushii'ig The inner wall B of the bushing is advantagcously tapered as shown to correspond to the taper ot' the plug C. For security against accidental displacei'nent, and to draw the parts snugly together on the initial closure of the hand hole, the plug 0 is l'lClVlllltfigQOll51:3 provided at its outer end with an nit-cruelly threaded extension C o't reduced diameter, which receives nut lG bearing against a washer D interposed between the inner end oi? the nut and the outer end of the hushing B.

Nith the described construction, it is obviously a simple matter to put the bushing; l3 and hand hole plug U in place in the first instance, and thereafter to open the passageway through tl'ie'bushiug, when this is necessary or desirable, by unscrewing the nut E and forcing the plug C inward, and to replace the plug and again close the passageway through the bushing. The fluid pressure acting against the inner end ot the plug C and tending to force the latter outward, tightens the joint between the plug and the bushing, and also tightens the threaded joint between the bushing); and the plate opening A, particularly when, as is ordinarily preferable, the bushing B is made of a suitable ductile material such as copper or mild steel. In such case the deformation of the bushing, when used in apparatus subjected to heavy internal pressure, may make it necessary to cut the bushing out of the opening A, it it becomes necessary to remove the bushing, but this is a comparatively simple and inexpensive operation, and when performed the destroyed bushing may be replaced by a new one Without injury to the plate A or to the hand hole plug C.

It will be obvious to those skilled in the art that various changes may be made in i he is normally the base oi the term oit construction illustrated in Figs. 1 and For trample, as shown in Fig. 3 a single element EB may replace and perform the function of the bushing 13 and Washer D oi l and 2. Also as s mum in Fig. the Washer meinher D of Figs. 1 and 2 may be replaced by a bushing member DD provided with a cylindrical flange portion D at its inner side which ahuts against the plate it and encircles the outer end of the hashing B piw'itecting the latter against accidental injury from maternal hlon-s or forces.

Having now described my invention What I claii'n as new and desire to hta'n by Letters Patent, is:

L The coinhinat 1 on with metallic chainher Wall :lornied r:

.th an opening 0' a rigid l lole metallic bushing inemher insert; into said opening from its outer end and lrnily L N :3

zinc.

secured therein, and a tapered lllQbZllliO h hole plug entering the inner end oi passage through said bushing and preventedby its taper from passing a. through the latter hut of a maximum entein ll dianie tor small enough to pass through said opening.

The combination with a metallic ch a1rleer Wall formed with a threaded opening of an externally threaded bushing of ductile metal screwed into said opening and a tapered ntietallic hand hole plug entering the inner end or? the passage through said hushing and orevented by its taper from passing axially through the latter but small enough in maximum external diameter to pass through said opening.

8. The combination With a metallic chainher Wall formed with a threaded opening of an externally threaded bushing of ductile metal screwed into said opening, and proflit) ridod with an outwardly projecting flange hearing agaii'ist the outer side ol' said Wall at the mar in of said hol and a tapered inolallic hand hole plug entering the inner end o the passage through the latter but small (nough in maximum external diameter to pass through sa d opening.

lThe con'ihination with a metallic chanther Well formed with an. opening oil a rigid metallic hushing threaded into said open-- in f from the outer side o'lj' said (llililllltl'r a taperrd. hand hole plug inserted into said lusi an the inner end oi the latter and 1 V y taprr ifroin passing as-zialh; t 1 l 'luit of in 'llll enough inanirs tlu'ough said oponinm z i i tiirrznled outer end. a nut 'lioi'eo and a cup shaped Waslu-r surrouiut ing mrcadcd end portion oi? the plug and till outer ind 0i the liushing and interposed lictirccu and nut and the haiuller llu: comliination with a metallic (hamwall formed. with a threaded opening o'l an externally threaded lii'ushing oi ductile metal saiewcd nto said opening, and pro ided with an outwardly projecting llange iearing against the outer side of said wall it the margin of said hole and a tapered rand hole plug entering the inner end of tun passage through the latter but small enough in maximum external diameter to 

